Process for the production of water and solvent-free halobutyl rubbers

Abstract

The present invention relates to water and solvent-free halogenated butyl rubber products as well as a process for the production thereof.

What is claimed is: 
     
       1. A process for removing volatile compounds from a fluid (F) containing 3 wt % to 50 wt % of at least one halogenated butyl rubber and 60 wt % to 97 wt % of volatile compounds comprising water and at least one volatile organic compound, whereby the halogenated butyl rubber and volatile compounds add up to 90 wt % to 100 wt % of the total mass of fluid (F), the process comprising:
 a) treating the fluid (F) in at least one concentrator unit comprising at least a heater, a degassing vessel comprising a flash evaporator in the shape of a cyclone, and a vapor line, the treating comprising heating the fluid (F) with the heater to provide a heated fluid (G), feeding the heated fluid (G) at a pressure of 2 to 60 bar into the degassing vessel, flashing at least a portion of the volatile compounds, and removing the flashed portion of the volatile compounds via the vapor line to produce a concentrated fluid (H) that is free-flowing and comprises 10 to 60 wt % of the rubber and 40 to 90 wt % of the volatile compounds, 
 b) reheating the concentrated fluid (H) in at least one reheating unit to obtain a reheated concentrated fluid (L) that is a free-flowing fluid; and 
 c) feeding the reheated concentrated fluid (L) into at least one extruder unit comprising at least an extruder degassing section comprising at least a conveying section, a vent port with one or more vapor lines, an accumulating section and an outlet section, to remove a portion of the volatile compounds through the vent ports and vapor lines to produce a product (P) at the outlet section that is substantially free of volatile compounds. 
 
     
     
       2. The process pursuant to  claim 1 , wherein:
 the pressure in the degassing vessel is 100 hPa to 4,000 hPa; and 
 the free-flowing concentrated fluid (H) comprises 10 to 60 wt % of the rubber, 25 to 90 wt % of volatile organic solvent, and 0.5 to 15 wt % water. 
 
     
     
       3. The process pursuant to  claim 1 , wherein the halogenated butyl rubber is bromobutyl rubber. 
     
     
       4. The process pursuant to  claim 2 , wherein:
 the heated fluid (G) is fed to the degassing vessel at a preswure of 4 to 30 bar; 
 the pressure in the degassing vessel is 200 hPa to 2,000 hPa; and 
 the free-flowing concentrated fluid (H) contains 25 to 60 wt % of the halogenated butyl rubber, 25 to 75 wt % of the volatile organic solvent, and 0.5 to 15 wt % water, whereby the halogenated butyl rubber, the volatile organic compound, and the water add up to 95 wt % to 100 wt % of the total mass of fluid (H). 
 
     
     
       5. The process pursuant to  claim 1 , wherein:
 the heated fluid (G) is fed into the top of the degassing vessel, 
 the degassing vessel has at least a torispherical shaped bottom outlet portion to facilitate removal of the concentrated fluid (H) from the degassing vessel, and 
 fluid (H) is pumped from the degassing vessel via a pump at the torishperical bottom portion, wherein the pump has an inlet with a cross sectional area A inlet  and the degassing vessel comprises an inner surface with an area A degas , wherein the ratio A inlet /A degas is 0.001≤A inlet /A degas ≤0.4 to reduce pressure drop at the inlet. 
 
     
     
       6. The process pursuant to  claim 1 , wherein the extruder unit comprises a single screw extruder or a multiscrew extruder. 
     
     
       7. The process pursuant to  claim 1 , wherein the extruder unit comprises a control device configured to operate separate zones of the extruder independently of each other at different temperatures so that the zones can either be heated, unheated or cooled independently of one another. 
     
     
       8. The process pursuant to  claim 1 , wherein the vent ports comprise stuffer screws to prevent the reheated concentrated fluid (L) or the product (P) from coming out of the vent ports. 
     
     
       9. The process pursuant to  claim 1 , further comprising adding a stripping agent in the extruder unit. 
     
     
       10. The process pursuant to  claim 1 , wherein the extruder unit comprises a feed point for receiving the fluid (L) and at least one additional extruder degassing section in an upstream direction of the feed point. 
     
     
       11. The process pursuant to  claim 1 , further comprising obtaining the fluid (F) from a process of removing hydrophilic compounds and optionally water from a crude fluid (A) containing at least one non-volatile polymer, at least one volatile organic compound, one or more hydrophilic compounds, and optionally water, wherein the process of removing hydrophilic compounds and optionally water from a crude fluid (A) comprises
 treating the crude fluid (A) in at least one pre-washing unit comprising at least a separating apparatus, the treating comprising mixing the fluid (A) with water to obtain an organic phase and an aqueous phase wherein the organic phase comprises primarily the non-volatile polymer and the volatile organic compounds and the aqueous phase comprises primarily water and hydrophilic compounds, 
 separating the organic phase from the aqueous phase in a separating apparatus, and 
 removing the organic phase as fluid (F). 
 
     
     
       12. The process pursuant to  claim 11 , further comprising obtaining the fluid (A) from a process comprising:
 I) providing a reaction medium comprising
 a common aliphatic medium comprising at least 50 wt. % of one or more aliphatic hydrocarbons having a boiling point of 45° C. to 80° C. at a pressure of 1013 hPa, and 
 a monomer mixture comprising at least one isoolefin monomer, at least one multiolefin monomer and either no or at least one other co-polymerizable monomer 
 in a mass ratio of monomer mixture to common aliphatic medium of 40:60 to 99:1; 
 
 II) polymerizing the monomer mixture within the reaction medium to form a rubber solution comprising a rubber polymer at least substantially dissolved in a mixture medium comprising the common aliphatic medium and residual monomers of the monomer mixture; 
 III) separating residual monomers of the monomer mixture from the rubber solution to form a separated rubber solution comprising the rubber polymer and the common aliphatic medium, and 
 IV) halogenating the rubber polymer in the separated rubber solution using halogenating agent to produce the fluid (A). 
 
     
     
       13. The process pursuant to  claim 12 , wherein the halogenating agent is a brominating agent. 
     
     
       14. The process pursuant to  claim 13 , further comprising at least partially regenerating the brominating agent by an oxidizing agent. 
     
     
       15. A process for producing a halogenated butyl rubber substantially free of volatile compounds, the process comprising:
 providing a reaction medium comprising
 a common aliphatic medium comprising at least 50 wt. % of one or more aliphatic hydrocarbons having a boiling point of 45° C. to 80° C. at a pressure of 1013 hPa, and 
 a monomer mixture comprising at least one isoolefin monomer, at least one multiolefin monomer and either no or at least one other co-polymerizable monomer 
 in a mass ratio of monomer mixture to common aliphatic medium of 40:60 to 99:1; 
 
 polymerizing the monomer mixture within the reaction medium to form a rubber solution comprising a rubber polymer at least substantially dissolved in a mixture medium comprising the common aliphatic medium and residual monomers of the monomer mixture; 
 separating residual monomers of the monomer mixture from the rubber solution to form a separated rubber solution comprising the rubber polymer and the common aliphatic medium; 
 halogenating the rubber polymer in the separated rubber solution using a halogenating agent to produce a fluid (F) containing 3 wt % to 50 wt % of at least one halogenated butyl rubber and 60 wt % to 97 wt % of volatile compounds comprising water and at least one volatile organic compound, whereby the halogenated butyl rubber and volatile compounds add up to 90 wt % to 100 wt % of the total mass of fluid (F); 
 treating the fluid (F) in at least one concentrator unit comprising at least a heater, a degassing vessel comprising a flash evaporator in the shape of a cyclone, and a vapor line, the treating comprising heating the fluid (F) with the heater to provide a heated fluid (G), feeding the heated fluid (G) into the degassing vessel, flashing at least a portion of the volatile compounds, and removing the flashed portion of the volatile compounds via the vapor line to produce a concentrated fluid (H) that is free-flowing and comprises 10 to 60 wt % of the rubber and 40 to 90 wt % of the volatile compounds; 
 reheating the concentrated fluid (H) in at least one reheating unit to obtain a reheated concentrated fluid (L) that is a free-flowing fluid; and 
 feeding the reheated concentrated fluid (L) into at least one extruder unit comprising at least an extruder degassing section comprising at least a conveying section, a vent port with one or more vapor lines, an accumulating section and an outlet section, to remove a portion of the volatile compounds through the vent ports and vapor lines to produce a product (P) at the outlet section that is substantially free of volatile compounds. 
 
     
     
       16. The process pursuant to  claim 15 , wherein the halogenating agent is a brominating agent. 
     
     
       17. The process pursuant to  claim 16 , further comprising at least partially regenerating the brominating agent by an oxidizing agent. 
     
     
       18. The process pursuant to  claim 4 , wherein the product (P) is a halobutyl rubber having a total concentration of volatile compounds of less than 0.5 wt % based on the mass of the halobutyl rubber. 
     
     
       19. The process pursuant to  claim 18 , wherein the product (P) is a halobutyl rubber having a residual water concentration of less than 0.25 wt %, and a residual organic solvent content of less than 0.25 wt %, based on the mass of the halobutyl rubber. 
     
     
       20. The process pursuant to  claim 18 , wherein:
 the degassing vessel has a shape of a cyclone and comprises an inlet at the top with a torispherical shaped bottom outlet portion disposed vertically below the inlet and comprising a fluid pump for feeding the fluid (H) from the degassing vessel to at least the reheating unit, wherein the process comprises feeding the heated fluid (G) into the degassing vessel via the top inlet, and pumping the fluid (H), via the fluid pump, from the bottom portion to the at least the reheating unit; and 
 the product (P) is a halobutyl rubber having a residual water concentration of less than 0.075 wt % and a residual organic solvent concentration of less than 0.1 wt %, based on the mass of the halobutyl rubber.